Speed control device



Oct. 6, 1959 J. J. GASPAROTTI SPEED CONTROL DEVICE Filed June 27, 1955 ATTORNEYS.

United States Patent SPEED CONTROL DEVICE John J. Gasparotti, St. Louis,

Monarch Company, Delaware Mo., assignor to Knapp- St. Louis, Mo., a corporation of This invention relates generally to a speed control device, and more particularly to a novel speed control linkage mechanism for an electrical food mixer of the portable hand type.

It is a primary object of this invention to provide a speed control device wherein straight-line motion of a sliding control knob effects positioning of a pair of electrical switch contacts relative to a speed responsive governor, whereby the predetermined motor speed at which the governor will effect opening and closing of the contacts may be adjusted.

It is another object to provide a novel linkage arrangement for translating the relatively long linear movement of a manual control knob into relatively short linear adjustment of a pair of governor-actuated contacts, whereby variable speed control of a motor at full power may be effected simply and accurately.

It is a further object to provide a novel linkage arrangement utilizing a substantially longitudinally elongated connector element for transmitting the relatively long linear movement of a slidable manual control knob to effect relatively short linear movement of a pair of adjustably positionable switch contacts.

Further objects and advantages of this invention will become apparent as the following description proceeds and the features of novelty which characterize this in vention will be pointed out with particularity in the claims annexed to and forming part of this specification.

A preferred embodiment of the invention is shown in the accompanying drawing, in which:

Figure 1 is a perspective view of an electrical hand mixer employing the speed control switch of the present invention;

Figure 2 is a side elevational view, partly broken away and in vertical section, showing internal structural details of a first embodiment of the mixer of Figure 1;

Figure 3 is a fragmentary view, similar to Figure 2, showing a modified form of the linkage of Figure 2;

Figure 4 is a top plan view, partly broken away and in horizontal section showing a hand mixer employing a speed control switch constituting an alternative embodiment of the present invention;

Figure 5 is a fragmentary view similar to Figure 4 showing a modified form of the linkage of Figure 4; and

Figure 6 is a perspective detail view, on an enlarged scale, of the sliding control knob employed in the constructions of Figures 4 and 5.

Referring now more particularly to Figures 1 to 3 of the drawing, I have indicated generally at 10 an electrical hand mixer of the type comprising a motor housing 12, a manual carrying handle 14, and a pair of mixer beaters 16. A combined speed control and on-oif switch 18 is positioned adjacent a top side corner of the mixer housing 12.

As bestseen in Figure 2, the housing 12 encloses an electrical motor 20 which is fixedly mounted therein. The motor 20 provides a rearwardly extending drive shaft 22 which carries an air circulating fan 24 and a speed control governor device 26. The governor 26 is fixedly secured to the shaft 22 at a terminal hub portion 28.

The governor comprises a pair of spiders 30 and 32 which are flexibly deformable and peripherally attached to each other. Suitable weights 34 are carried by the spiders 30, 32 for effecting flattening deformation of the spiders toward each other by centrifugal force when rotated at high speeds. The rearrnost spider 32 carries an actuator button 36 at its center portion, and serves to effect longitudinal movement thereof as the spider assembly is flexibly deformed.

A resilient spring blade 38 is disposed adjacent the button 36, and carries an electrical contact 40 for cooperation with a second contact 42. The contact 42 and the spring blade 38 are carried by a bendable bracket 44. Normally, the contacts 40 and 42 are spaced from each other. The bracket 44 is secured to the housing 12 by a resiliently bendable connector element 46.

The housing 12 is formed with an axially elongated slot 50 along which a slider knob 52 is adapted to move. A pin shaft 54 of the knob 52 extends inwardly through the slot 50 and carries a push-on type of speed clip 53 at its terminal end within the housing 12. In this way, the knob 52 is securely retained for sliding movement along the slot 50. The pin shaft 54 cooperates with the yoked end 56 of a lever 58, effecting a mechanical coupling therebetween. The lever 58 is centrally pivoted at 60 on a suitable fixed element within the housing 12. In this way, sliding movement of the knob 52 effects a pivoting of the lever 58, as shown by the dotted line position of Figure 2.

A substantially elongated actuator rod 62 is pivotally connected at its forward end to the lower end of thelever 58, and is fixedly secured at its rearward end to the free end of the bendable bracket 44. It will be apparent that sliding movement of the knob 52, and consequent pivoting of the lever 58, will serve to effect longitudinal shifting movement of the actuator rod 62. In this way, the bendable bracket 44 can be positioned relative to the actuator button 36 of the governor 26. By predetermining the relative compression between the actuator button 36 and the spring blade 38, the motor speed at which deformation of the spiders 30, 32 will effect opening and closing of the contacts 40, 42 can be selected. When a separating distance exists between the actuator button 36 and the spring blade 38, the normally spaced contacts 40, 42 provide an off circuit position. When the slider knob 52 is moved a sufiicient distance, the contacts 40, 42 will be closed by engagement with the actuator button 36. When the motor reaches a sufficiently high speed, determined by the particular position of the knob 52, the spiders 30, 32 will deform and effect withdrawal of the button 36 so as to permit opening of the contacts 40, 42. In this way motor speed may be effectively regulated.

In Figure 3 of the drawing, I have shown a modification of the linkage arrangement of Figure 2. If it is desired to reverse the direction of movement of the slider knob 52, with respect to the front and rear of the mixer housing 12, the pivot point for the lever 58 may be located at the lower end of the lever rather than intermediately thereof as in Figure 2. This modified location for pivotal connection is indicated at 60a on Figure 3. The forward end of the actuator rod 62 is then pivotally secured to the lever 58 intermediate the pivot 60a and the yoked end 56. The operation of the linkage is substantially identical in basic principle as heretofore described, except that the off and high positions for motor speed adjustment are reversed relative to the front and rear of the mixer housing 12. In the arrangement of Figure 2, rearward movement of the slider 52 is from elf-" to high, whereas in the arrangement of Figure 3 V sliding cooperation with the registered slots 72 and 72a.

As shown in Figure 6, the knob 74 provides a pair of inwardly extending spaced ears 76 within the interior of the housing 12. These spaced ears are apertured'as indicated at 78 to receive therethrough a length of flexible wire or other suitable line material 80. The wire 80 is fastened at its forward end to an inwardly extending arm portion 82 of the bracket 70, as indicated at 84. The wire 80 is fastened at its rear end to the bendable contacts bracket 44, as indicated at 86.

,In this way, longitudinal sliding movement of the knob 74 along the slots 72, 72a serves to effect a variation in the angle between points 847686, and thereby provide a pulling or releasing force on the portion of wire length extending between the knob 74 and the bendable bracket 44. By moving the slider knob 74 in a forward direction (to the left as seen in Figure 4) a pulling force will be exerted on the bracket 44 effecting a forward bending movement thereof and consequent close cooperative positioning of the actuator button 36 and the contacts 40,- 42 of the governor mechanism. High speed operation of the motor is thereby obtained. Similarly, reverse movement of the slider knob 74 will eifect a sufficient release of the tensioning of wire 80 so as to provide an off position of contact separation.

In Figure 5 of the drawing, I have illustrated a modification of the linkage arrangement of Figure 4, wherein a tension spring 90 is provided in the length of wire 30 between the points 76 and 86 The forward end of the wire 80 is not connected to the bracket arm 82, but terminates at the forward ear 76 of the slider knob 74. Thejuse of the tension spring 90 in the wire length 80 results in a still smaller relative movement of the bendable bracket 44, when the slider knob 74 is moved to its full longitudinal range of adjustment. In this way, very small adjusting movement of the governor contacts may beeffected by substantially long control knob movement.

, By the present invention I have provided an extremely simple and low cost form of speed control switch for a mixing device having a coupling arrangement wherein substantial longitudinal movement of a control knob serves to effect relatively small and therefore fine adjusting movements for regulating the operation of a motor speed governor. The present invention accomplishes this purpose without the necessity for complex and costly multi-position electrical switches.

Changes may be made in the construction and arrangemerit of the parts of my speed control device without departing from the real spirit and purpose of my invention, and it is my intention to cover by the claims any modified forms of structure or use of mechanical improvements which may be reasonably included within their scope.

What I clairnas newand desire to obtain by Letters Patent; of the United States is:

p l'. A. speed control device for an electrical appliance motor comprising a finger'actuated control knob adapted to be mounted for longitudinal sliding momevent to control motor speed through a range of speeds including an "01? positioinand linkage means for interconnecting said control knob to a variably positionable switch mounting means, saidjlinka'ge means including a lever pivoted in fixed location relative to the path of movement of said controlfknob', a longitudinallyelongated actuator member substantially greater length than, and'disp'osed generally parallel to, the path of movement of said control knob, said actuator member having its one end pivotally secured to said lever and having its other end adapted to be secured to a remote variably positionable switch mounting means having a limited range of movement, said lever being pivotally connected to said control knob, the distance from said fixed pivot to said pivotal connection between the actuator member and the lever being substantially short in length relative to the path of movernent of said control knob, whereby relatively long longitudinal movement of said control knob serves to effect parallel and relatively short longitudinal shifting of said actuator member. 7 i

2. A speed control device for'an electrical appliance motor comprising a finger actuated control knob adapted to be mounted for longitudinal sliding movement to control motor speed through a range of speeds including an off position, and linkage means for interconnecting said control knob to a variably positionable switch mounting means,- said linkage means including a lever pivoted in fixed location relative to the path of movement of said control knob, a longitudinally elongated actuator member or substantially greater length than, and disposed generally parallel to, the path of movement of said control knob, said actuator member having its one end pivotally secured to said lever and having its other end adapted to be secured to a remote variably positionable switch mounting means having a limited range of movement,

. said lever having an open yoke portion at a free end thereof to efiect loose coupled engagement with said control knob, straight line movement of said control knob being thereby transmitted through said yoke coupling to effect arcuate movement of said lever about its fixed pivot, the distance from said fixed pivotto said pivotal connection between the actuator member and the lever being substantially short in length relative to the path of movement of said control knob, whereby relatively long longi tudinal; movement of said control knob serves to effect parallel and relatively short longitudinal shifting of said actuator member.

3. A speed control device for an electrical appliance motor comprising a finger actuated control knob adapted to be mounted for longitudinal sliding movement to control motor speed and including an oil position, and linkage means for interconnecting said control knob to a variably positionable switch mounting means,- said linkage means including a lever pivoted in fixed location relative to the path of movement of said control knob, a longitudinally elongated actuator member of substantially greater length than, and disposed generally parallel to, the path of movement of said control knob, said actuator member having its one end pivotally secured to said lever at one side of said fixed pivot and having its other end adapted to be secured to a remote variably positionable switch mounting means having a limited range of movement, said lever being pivotally coupled to said control knob at the other side ofsaid fixed pivot, the distance from said fixed pivot to said pivotal connection between the actuator member and the lever being substantially short in length relative to the path of movement of said control knob, whereby relatively long longitudinal movemerit of said control knob serves to effect parallel and relatively short longitudinal shifting of said actuator member. V 1 p 4. A speed control device for an electrical appliance motor comprising a finger actuated control knob adapted to be mounted for longitudinal sliding movement to control motor speed and including an to position, and linkage means for interconnecting said control knob to a variably positionable switch mounting means, said linkage means including a lever having its one end pivoted in fixed location relative to the path of movement of said control knob, a longitudinally elongated actuator member disposed generally parallel to the path of movement of said control knob, said actuator member havingi-ts one end pivotally secured to said lever intermediate said fixedly pivoted end and the other end thereof, said actuator member having its other end adapted to be secured to a variably positionable switch mounting means having a range of movement, said lever being pivotally coupled at its said other end to said control knob, the distance from said fixed pivot to said pivotal connection between the actuator member and the lever being substantially short in length relative to the path of movement of said control knob, whereby relatively long longitudinal movement of said control knob serves to eifect parallel and relatively short longitudinal shifting of said actuator member.

References Cited in the file of this patent UNITED STATES PATENTS 1,182,723 Waldmeier May 9, 1916 6 Butler Apr. 12, 1932 Adam Sept. 13, 1932 Green Apr. 20, 1943 Zilliotto Nov. 15, 1949 Valpey Oct. 31, 1950 Benning Nov. 20, 1951 Van Guilder Nov. 4, 1952 Holstein Dec. 30, 1952 Buckman et a1 Feb. 18, 1958 Mall et a1. Apr. 8, 1958 FOREIGN PATENTS Italy Oct. 10, 1938 

